Apparatus for making helical electric resistance heating wire coils and provided with a rotary mandrel and a pressing roll having an elastically deformable coil embracing surface



20, 1959 P. CICCONE ETAL 2,909,209

APPARATUS FOR MAKING HELICAL ELECTRIC RESISTANCE HEATING WIRE COILS ANDPROVIDED WITH A ROTARY MANDREL AND A PRESSING ROLL HAVING AN ELASTICALLYDEFORMABLE COIL EMBRACING SURFACE Filed May 24 1954 g 6% 5 m f APPARATUSFOR MAKING HELICAL ELECTRIC RESISTANCE HEATING WIRE COILS AND PRO- VIDEDWITH A ROTARY MANDREL AND A PRESSING ROLL HAVING AN ELASTICALLYDEFORMABLE COIL EMBRACING SURFACE Patsy Ciccone, Cranford, and WilliamWalterWallin, Kearny, NJ., assignors to Driver-Harris Company, Harrison,N.J., a corporation of New Jersey Application May 24, 1954, Serial No.431,791

1 Claim. c1. ass-s4 gauges of wire, such as 30 B. &- S. gauge, in anautomatic manner with the resulting coils having their convolutionsstrained so uniformly that when a coil is pulled apart or extendedlongitudinally each convolution separates from the other substantiallyequal amounts throughout the coils length. This is important becausesuch coils are frequently operated very close to their meltingtemperatures and if two adjacent convolutions fail to separate as muchas the others, these convolutions overheat and result in destruction ofthe coil as a useful heating element. For a similar reason it isimportant that the wire be coiled without nicking it or otherwiselocally reducing its diameter.

Such automatic wire coiling became possible because of the developmentof the invention disclosed and claimed by the Stephen A. Plattapplication Serial No. 251,053, filed October 12, 195 1, and nowabandoned. A machine constructed in accordance with the said Plattinvention features a rotatively powered rotary mandrel having a smoothcylindrical surface terminating with a free end. Means are provided forfeeding wire transversely to a portion of the mandrels surface spacedfrom its free end and at least one rotary roller is provided which has afree end extending in the direction of the mandrels free end and havinga peripheral surface positioned to bear in a rolling manner on thewirewhen it is helically wound on the mandrels mentioned portion; Thisrolling surface is contoured so as to be spaced free from the mandrelwhen bearing on the wire wound thereon and the surface of this roller,like that of the mandrel, extends in an axially smooth fashion to therollers free end. The wire is coated with a liquid lubricant and is wetwith this lubricant while it is wound on the mandrel, the desiredhelicalcoil growing from its point of feed and sliding therefrom axiallypast the free ends of the mandrel and roller and away therefrom as acontinuously traveling coil. At least one other rotary roller provides arigid rotary abutment surface extending radially.

with respect to the mandrel and located adjacent to the end of themandrel portion carrying the convolutions which is most remote from themandrels free end; This abutment surface is arranged to abut the firstof the convolutions formed by the wire fed to this mandrel portion,whereby to prevent the coil from backing up oppositely to the growingdirection of the coil.

Due to the above arrangement the rollers and mandrel may be rotated atdifferent relative speeds and this to gether with the use of liquidlubrication and the other contributing features has permitted thecoiling of electric resistance wire coils when using wire gauges down tothe 30 B. & S. gauge mentioned.

J Un d St f P re MC? In the case of finer wires these automatic coilingma chines have experienced operational troubles. In some instances suchfine wire could be coiled but the machine. could be set up initiallyonly with considerable difficultyl These machines are familiar toeveryone skilled in the coiling of electric resistance heating wirecoils and, as is. well known, they must be adjusted by varying rollerangularities, roller speeds and pressures, as related'to the mandrel andthe wire coiling thereon, and the like. These usual adjustments havebeen very ditficult or impossible to make in the case of very finewirecoiling.

One of the objects of the present invention is to prove on the machinesincorporating said Platt invention of the mentioned application, in sucha fashion as to' permit that type of machine to be satisfactorily usedin the case of the very fine wire gauges. Another, object is to providea method of Wire coiling permitting the coiling of helical coils fromsuch fine gauge wire. The present invention has commercially provenitself to be fully capable of satisfactorily attaining these objectives;

The accompanying drawings illustrate a specific ex-,

. ample of the described kind of wire coiling machine which has beenimproved by the incorporation of the present invention, the variousfigures being as follows:

Fig. 1 is an end elevation showing the end of the machine away fromwhich the coil feeds;

Fig. 2 is a top view of the machine;

Fig. 3 is an enlarged view showing the coiling action; Fig. 4 is ahorizontal section taken centrally through Fig. 3; and

Fig. 5 shows an important element used in connection T with theimprovement.

. maintained in a pan 19. This coats the entire surface These drawingsare somewhat schematic in character and they show a rotating chuck 1which extends through. a housing 2 to an external pulley 3 which may beconnected by a belt to an electric motor. The shaft mounting the chuck 1is journaled in the housing 2 so as to rotate very smoothly. Thedescribed mandrel 4 is gripped by the chuck 1 and extends forwardlytherefrom in an axially smooth manner and so as to terminate with, thefree end 5. The usual two rollers 6 and 7 are journaled in brackets 8and 9, respectively, these brackets having inwardly extending arms 10and 11, respectively, which mount the brackets on a pivot 12. The weightof the rollers and of the arms causes outward motion but this weight isoverbalanced, so that the rollers may be moved together, by a tensionspring 13 provided with a tension adjusting screw 14. This springextends trans versely so as to interconnect the two brackets 8 and 9.

These rollers are rotatively powered so as to turn in synchronousspeeds, this being done through the flexible shafts 15 which extendthrough openings in the housing 2 and which are appropriately rotativelypowered by equipment inside of the housing 2. The rotation of the shafts'15 and. hence of the rollers 6 and 7, is entirely independent of themandrel 4 which is rotated by driving the pulley 3. Of course, thedirections of rotation are such as to wind or coil the wire.

As iswell known to all commercial users of this kind of machine, therollers 6 and 7 are constructed so as to mount various annular tools orrings which are used in connection with the coiling operation. I

The wire 16 is continuously drawn from an unillus trated supply reeldownwardly and is bent around the bottom of a sheave 17 which isjournaled so that its bottom runs beneath the level of a liquidlubricant 18' of the wire with the liquid lubricant, the wire thenfeeding upwardly and transversely on a portion of the spindle 4 which isspaced from the spindles free end 5.

Various liquid lubricants may be used, asoap and water solution, a wateremulsion of a lubricating oil and;

Patented Oct. 20,

3 the like being suitable. Lubricants of this type are often used in thewire working art in general. This total or complete lubrication of the.wire has the advantage of causing the convolutions of the coil producedby the machine, to be uniformly strained was to get the desired kind ofuniform extension when the coil is placed in. service. The lubricationprevents the formation of nicks. or other localized deformations such asmight be caused, in the absence of the lubrication, because of theindependence between the mandrel 4 and the rollers 6 and 7. The use ofthis lubrication is characteristic of the: describedtype of machine.

Heretofore the tools or rings used on the rollers 6 and 7 have been madeof metal and, therefore, rigid.

This was thought to be necessary to obtain a proper drive on. the. wireduring its coiling, the lubricated metal-tometal surfaces smoothlyurging the wire to coil.

The present invention diverges from what was Previously known and usesan elastically deformable ring 20 which is mounted on the roller 6. Thisroller is connected to its shaft so as to be rotatively powered thereby.The surface of this roller is cylindrical and smooth, the surface, ofcourse, terminating with a free end 21 extending in the direction of thefree end 5. As is illustrated, the elastically deformable part is in theform of a tire 22 having a fiat, cylindrical tread forming the surface20, and mounted firmly on a rigid supporting ring 23. This permits theunit to be mounted on the roller 6 in the usual manner. The elasticdeforrnability should be sufficient to provide for a cushioning effectwhen acting on the coiled wire but it should not be so softly elastic asto contact the mandrel 4 by deforming or bulging, when the roller 6 hasproper operating force or pressure applied to it by the spring 13. Theelastic deformable ring 20 on the roller 6 is positioned in such amanner that the tire 22 extends beyond the rear of the firstconvolution. The forming of the first convolution is controlled by therolling action of the elastically deformable ring 20 which partiallyembraces the rear side of the first convolution without contacting themandrel (see Fig. 4).

The other roller 7 is provided with only the back-up ring 24 whichprevents the helically coiled wire from backing up in a directionopposite to the growing direction of the coil. This ring provides arigid rotary abutment surface 25 extending radially with respect to themandrel 4 and located adjacent to the end of the mandrels portion towhich the wire is transversely fed and which end is the one most remotefrom the mandrels free end. This ring 24 is arranged so that its surface25 abuts the first of the convolutions formed by the wire fed to thisportion of the mandrel and to thus prevent the coil from backingbackwardly along the mandrel 4. Since the pan 19 containing thelubricant 18 is located so as to coat the wire before it reaches thesurface '25, there is plenty of liquid lubricant between this wire andthe surface at all times.

With this new improvement very fine gauge electric resistance heatingwire may be helically coiled in the precision manner required for thereasons previously explained.

The wire 16 is fed transversely to the axially elongated rotatingsurface, provided by the mandrel 4, and is wound helically around thismandrel for a plurality of convolutions so as to form the helical coil,shown at 2-6 growing axially away from the location to which the Wire istransversely fed. The elastically deformable rotating surface 20 ispressed rollingly against the outside of the convolu tions so that thelatter are radially engaged between the surfaces. Everything is soakedwith slippery lubricant and it would ordinarily be supposed that rubber,deformable plastics, and other similar elastically deformable materialsuch as must be used to provide the described type of surface, would beso slippery as to be ineffectiveas adriving element. However, actualpractical experience has shown that a proper drive is easily effected.

The elastically deformable surface causes even fine wire to coilproperly when gripped between the clastically deformable surface and themandrel 4. Depending on the rotative speeds of the mandrel and of theelastic surface, the coil is more or less larger in diam eter than themandrel 4. The rigidly positioned rigid surface 25 prevents the Wirecoil from going backwards and forces it to grow or feed forwardly whilesliding relative to the mandrel 4 and in many cases relative to thesurface 20.

As the described kinds of machines are ordinarily constructed, the ring24 will peripherally engage the mandrel 4 when used without a pressurerolling ring as is contemplated by the present invention. Because of thelarge amount of liquid lubrication existing everywhere throughout thecoiling zone, this need not prevent the operation of the roller 7 at aperipheral speed different from that of the mandrel 4. In some instancesthe roller 7 may be unkeyed or disconnected so that it is not driven byits shaft 15. As shown by the drawings, the bracket 9 may be providedwith an extension 27 which mounts an adjustable stop 28 which engagesthe housing '2 so as to space the periphery of the ring 24 from themandrel 4 in the manner shown by Fig. 4.

It is to be noted that the present improvement permits the coiling ofsuch fine wire so as to make satisfactory electric heating resistancecoils because the wire is in effect spun on the mandrel 4 with theelastic surface 20 serving to hold the very fine wire more gently thanbefore and while gently urging the wire to coil. As indicated, the tire22 may be made of rubber or the like. Although everything is coated withliquid lubricant there is still sufficient drive, perhaps in a slidingor skidding manner, to urge the wire to coil. In any event, it is' amatter of fact that with the use of the present inven'-' tion it is nowpossible to automatically coil even finer gauge wire than could behandled by the machine made available to industry by the invention ofthe previously: mentioned Platt application. The coils produced have allthe characteristics required for use as electric resistance heatingcoils and the coiling is carried out continuously and withoutinterruptions once it has been started properly. It is to be understoodthat a suitable knife cuts the continuously growing coil into thedesired lengths at the delivery end of the coiling machine.

As indicated, the mandrel and the deformable roll otfer substantially noimpedance to the growing coil in its growing direction. The elasticsurface deforms slightly but not so much as to contact the mandrel.

We claim:

A helical wire coil winding machine including a rotary mandrel having afree end, means for feeding wire transversely to a portion of themandrels surface spaced from its said end, at least one rotary rollerhaving a free end extending in the direction of the mandrels free endand having an elastically deformable peripheral surface positioned tobear in a rolling manner on at least the first convolution of the wireand extending rearwardly of said convolution as it is helically wound onthe mandrels said portion, said elastically deformable surface beingcontoured so as to be spaced free from the mandrel when bearing on thewire wound thereon and to partially embrace the rear side of saidconvolution all of said surfaces extending to said free ends so that asthe wire is continuously wound on the mandrels said portion theresulting helical coil growing thereon may slide therefrom axially pastsaid free ends and away therefrom as a continuously traveling coil, andmeans for wetting the wire with liquid lubricant so that the wire is wettherewith while wound on said mandrel and While contacted by the rollerssaidsurface, and at least one other rotary roller providing a rigidrotary abutment surface extending radially with respect to said mandrel.and located ad' 5 jacent to the end of the mandrels said portion mostremote from the mandrels free end so as to abut said rear side of saidfirst convolution formed by the wire fed to this portion and prevent thecoil from backing up oppositely to the growing direction of the coil.

References Cited in the file of this patent UNITED STATES PATENTS121,831 Weber Dec. 12, 1871 372,423 Mallet-Guy Nov. 1, 1887 1,243,179James Oct. 16, 1917 1,953,502 Reimers Apr. 3, 1934

